Biology, 26.02.2020 05:02 nettyshaf202406
A host organism needs time, often days, to mount an immune response against a new antigen, but memory cells permit a rapid response to pathogens previously encountered. A vaccine to protect against a particular viral infection often consists of weakened or killed virus or isolated proteins from a viral protein coat. When injected into a person, the vaccine generally does not cause an infection and illness, but it effectively teaches the immune system what the viral particles look like, stimulating the production of memory cells. On subsequent infection, memory cells recognize and bind to the virus and trigger a rapid immune making it difficult or impossible to develop effective vaccines against them. Some pathogens, including HIV, have developed mechanisms to evade the immune system, Assume that a host's antibodies and T-cell receptors are available to bind to any structure that might appear on the surface of a pathogen and that, once bound, the pathogen is destroyed. What strategy could a pathogenic virus use to evade the immune system? A. The virus can target, infect, and destroy immune system cells. B. The viral surface proteins mutate rapidly. C. The viral particles do not encode proteins. D. The virus does not produce antibodies. E. Viral particles prevent immune cells from making antibodies.
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Biology, 21.06.2019 21:00
What two fields of study provide the core information that is used to classify organisms?
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Biology, 22.06.2019 00:00
Theories basic to all of the life sciences include the germ theory of disease. theory of evolution by natural selection. o two of these answers are correct none of these answers are correct o cell theory.
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Biology, 22.06.2019 17:40
You find a fossil that you are sure shows evidence of bipedalism. you know this because which of the following anatomical traits is present? a. thighbones that angle in toward the knees b. a narrow pelvis c. opposable hallux d. posterior position of the foramen magnum
Answers: 1
A host organism needs time, often days, to mount an immune response against a new antigen, but memor...
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